Optical Receivers
摘要
The basis of all receivers in optical transmission is the internal photoelectric effect. The simplest receiver is the p-n photo diode, which is very slow due to diffusion. The fastest receiver is the p-n photo diode, which can be very fast due to drift. The most sensitive receiver is the avalanche photo diode (APD), where the sensitivity is achieved by the avalanche-like multiplication of the electrons in the p-n junction. The noise processes such as shot noise, intensity noise, thermal Nyquist noise, and multiplication noise and their influence on the bit-error rate BER are described in detail. Optical heterodyning as a very sensitive alternative for the future is explained.